Removing Miata Engine and Transmission

Getting down to the nitty-gritty on the '94 Miata. This weekend I yanked out the shortblock and transmission together, separated them, and got the engine up on the stand where I can work on it.

With the head off, I had nothing to hook onto with the hoist so I used four old head bolts threaded into the block. It worked like a charm and I was able to pull the whole assembly out by myself without any help. I did discover at the last minute that the hood had to come off, but it's only 4 nuts so I was able to take it off and get it out of the way easily.

Once the assembly was out, it was very easy to separate the block from the transmission. The hard part was then getting the flywheel bolts out. They are installed with quite a bit of tourque and the engine just wants to spin. My impact wrench is not a very good one (need to fix that) so it wouldn't budge the flywheel bolts at all. Absent an impact wrench, the only way to attack it is to somehow lock the flywheel so you can wrench on the bolts without the engine spinning. I did that using the attachment arms from my engine stand, but some steel strapping can be used to the same effect. From there, I used a breaker bar and the handle from my floorjack and was able to get the bolts loose.

With the short block on the stand, I then cleaned the deck of the block and used some aluminized tape (not duct tape but the stuff A/C contractors use to seal duct work) to cover the top of the block so I didn't get water on top of the pistons in the next step.

The engine bay is just about empty. I bagged the connector-ends of the wiring harness and covered the fuse block and the relays as best as I could. The next step there is to prep and paint the subframe and front suspension. Then paint the engine bay.

Just as I suspected there was a bad rear main seal leak. The bellhousing was very oily and messy. The clutch was fine, though.

The next step involved a pressure washer and a bunch of Purple Power. I pressure washed the engine bay, front subframe, and everything else I could get to in the front of the car (great opportunity to really clean out the A/C condensor). Then I pressure washed the transmission and the short block, using plenty of degreaser.

Nice clean tranny. I will probably paint it with Eastwood Aluma-blast.

Here's a few more photos in no particular order to help fill in some gaps.

Depths of the Engine

This weekend I got the head off the engine and I'm ready to continue pulling parts off the block and get it ready to come out as well. I'll pull the block and transmission together, most likely. Overall, the block looks fine. The cylinder wall don't show any scoring or ridges at all, and the cross-hatching is still visible in most places. I'm not planning to tear it down to take measurements because it still had great compression and didn't burn any oil before I started this whole thing.

There's a bit of carbon on the piston tops, but not too much, and the valves and spark plugs look like the engine was running very lean, despite the fact that I thought I had fixed my lean running issue a couple months ago. For sure I was getting less pinging, but I think there may still be a problem. If it's an engine management problem then it will probably still be there when I finish this project because I'm not messing with that.

My good friend Steve offered up a complete cylinder head and intake manifold from a '99 Miata and I'm going to take him up on it. It's a direct bolt-on for this engine and the improvements Mazda made over the '94-'97 head (shown here) were extensive. It's probably good for 7-10 horsepower, which is a lot for these cars. So this head I just yanked out will probably not get reused. Neither will the '96 head I have that I was planning to use. So maybe I can sell both of those and recoup some of my expenses on this project.

Next on the agenda is to get the accessories and the water pump pulled off the front of the short block, and continue stripping the engine compartment so I can paint it. I'm starting to order more parts for the mechanicals. Last night I ordered Mazda Competition motor mounts and a long braided clutch hose from 949 Racing. Also, in the interest of shaving a bit off the budget anywhere I can, I'm going with a clutch and flywheel package from eBay. It's an 11 pound flywheel (stock is close to 20) and an OEM equivalent Exedy clutch and pressure plate, all for under $300. Normally I'm plenty skeptical of cheap car parts, but these have gotten consistently good reviews on the forums so I'm willing to take a bit of a chance since it saves almost $150 over what I had originally planned to get. Also the frame rail reinforcement kit from Flyin' Miata is inbound on the big brown truck from Colorado.

The budget is starting to come into focus as well. Depending on how I cook up the numbers, and counting a few things I've already bought, assuming a budget of about $500 to paint the car myself, and budgeting for a new set of wheels and tires, the total comes to about $3500. Not a bad deal when you consider how cool this car will be and how it will be good for another 10+ years of worry-free driving. That's my theory anyway.

Here's a color I was toying around with. I used Forza on the XBOX to mock up the car with the color and a representative set of wheels. It's between this color and keeping it red. Keeping it red would certainly be less work.